Multi-segment monolithic LED chip

ABSTRACT

Described herein are LED chips comprising pluralities of active regions on the same submount. These active regions are individually addressable, such that beam output from the LEDs can be controlled simply by selectively activating the desired active region in the plurality without resorting to incorporation of advanced optics and reflectors comprising complex moving parts. In some embodiments, one or more active regions can surround one or more other active regions. In some embodiments, the various active regions are individually addressable by virtue of each active region comprising its own anode and sharing a common cathode. In some embodiments, the various active regions are individually addressable by virtue of each active region comprising its own cathode and sharing a common anode. In some embodiments, each active region comprises its own anode and its own cathode.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of, and claims the benefitof, U.S. patent application Ser. No. 13/801,743 to Michael JohnBergmann, et al., entitled WAFER LEVEL PACKAGING OF MULTIPLE LIGHTEMITTING DIODES (LEDS) ON A SINGLE CARRIER DIE, filed on Mar. 13, 2013,issued as U.S. Pat. No. 9,666,764, which claims priority from: U.S.Provisional Application Ser. No. 61/727,524, filed on Nov. 16, 2012,U.S. Provisional Application Ser. No. 61/621,746, filed on Apr. 9, 2012,and is a continuation in part of Ser. No. 13/608,397, filed on Sep. 10,2012, issued as U.S. Pat. No. 9,653,643, all of which are herebyincorporated herein in their entirety by reference. This application isalso a continuation in part of and claims the benefit of U.S. patentapplication Ser. No. 14/050,001 to Kevin W. Haberern, et al., entitledHIGH VOLTAGE MONOLITHIC LED CHIP, filed on Oct. 9, 2013, issued as U.S.Pat. No. 9,728,676, which is a continuation in part of Ser. No.13/168,689, filed on Jun. 24, 2011, now issued as U.S. Pat. No.8,686,429, both of which are hereby incorporated herein in theirentirety by reference.

BACKGROUND Field of the Invention

Described herein are devices relating generally to light emitting diode(LED) chips, and specifically LED chips comprising multiple activeregions.

Description of the Related Art

LED-based light emitting devices are increasingly being used inlighting/illumination applications, with one ultimate goal being areplacement for the ubiquitous incandescent light bulb. SemiconductorLEDs are widely known solid-state lighting elements that are capable ofgenerating light upon application of voltage thereto. LEDs generallycomprise a diode region having first and second opposing faces, andincluding therein an n-type doped layer, a p-type doped layer and a p-njunction active region. An anode contact ohmically contacts the p-typelayer and a cathode contact ohmically contacts the n-type layer. When abias is applied across the doped layers, holes and electrons areinjected into the active region where they recombine to generate light.Light is produced in the active region and emitted from one or moreemission surfaces of the LED.

The diode region may be epitaxially formed on a substrate, such as asapphire, silicon, silicon carbide, gallium arsenide, gallium nitride,etc., growth substrate, but such a substrate can be later removed andthe completed device may not include a substrate. The diode region maybe fabricated, for example, from silicon carbide, gallium nitride,gallium phosphide, aluminum nitride, indium gallium nitride, aluminumgallium nitride, aluminum indium gallium phosphide and/or galliumarsenide-based materials and/or from organic semiconductor-basedmaterials.

An example of a conventional LED structure as discussed above is shownin FIG. 1, which illustrates an example LED chip 10, comprising a dioderegion 11, which comprises an n-type layer 12, a p-type layer 14, and anactive region 16 between the two layers. The diode region 11 is on asubmount 18. The submount 18 is typically a substrate as discussed aboveand can be the growth substrate upon which the diode region isepitaxially formed, or in the case of flip-chip embodiments, can be thecarrier substrate to which the diode region is transferred from thegrowth substrate. FIG. 1 also shows a cathode contact 20 in the form ofa bond pad contacting the n-type layer 12 and an anode contact 22contacting the p-type layer 14, for example via a conductive substrate18. While the conventional LED example of FIG. 1 shows the n-type layer12 as the topmost layer of the diode region 11 and the p-type layer 14as the bottommost layer of the diode region, many conventional LEDs havea structure with the p-type layer 14 as the topmost layer of the dioderegion 11 and the n-type layer 12 as the bottommost.

Most typical LED chips have a single active region, although some LEDpackages comprise a plurality of active regions in the form of multiplejunctions or sub-LEDs, such as those disclosed in U.S. Pat. No.7,985,970, and U.S. Patent Pub. No. 2010/0252840 (both assigned to CreeInc. and hereby incorporated herein in their entirety by reference).

One problem with current LED technology is that each physical LED chipis limited to being controlled in series for the entire emission region,resulting in all emission regions in a multiple-junction (high-voltage)device being controlled together. Since multiple active regions on thesame chip are not independently controlled, in order to vary emission toadjust the emission beam angle or achieve a particular desired emissionpattern for the LED chip, complex structures, such as moving mirror orreflector structures, must be incorporated with the device. Thisincreases the cost of manufacturing lighting devices and increases thenumber of additional components in the device, decreasing efficiency andincreasing the chance of device malfunction.

SUMMARY

Described herein are LED chips comprising pluralities of active regionson the same submount that are individually addressable, such that atleast two active regions in the plurality of active regions can beactivated independently from one another, allowing for adjustment ofbeam output profiles though selective activation of the various activeregions.

In some embodiments, one or more of the active regions in the pluralitysurround other active regions in the plurality. In some embodiments, theactive regions are configured adjacent to each other in successiveorder. In some embodiments, the multiple active regions share a commoncathode contact and each have individual anode contacts. In someembodiments, the multiple active regions share a common anode contactand each have individual cathode contacts. In some embodiments, themultiple active regions each comprise their own separate anode andcathode contacts.

In one embodiment, an LED chip comprises a submount, a plurality ofactive regions on the submount and connection elements in electricalcontact with the plurality of active regions. The connection elementsare configured such that at least one active region in the plurality canreceive an electrical signal independent from other active regions inthe plurality.

In another embodiment, an LED chip comprises a submount, a plurality ofactive regions on the submount, with at least one of the active regionsin the plurality surrounding another of the active regions in theplurality, and connection elements in electrical contact with theplurality of active regions. The connection elements are configured suchthat at least one active region in the plurality can receive anelectrical signal independent from other active regions in theplurality.

In yet another embodiment, an LED chip comprises a submount, a pluralityof active regions on the submount and adjacent to one another insuccessive order and connection elements in electrical contact with theplurality of active regions. The connection elements are configured suchthat at least one active region in the plurality can receive anelectrical signal independent from other active regions in theplurality.

In still another embodiment, a light emitting device comprises an LEDchip and a reflector. The LED chip comprises a submount, a plurality ofactive regions on the submount and connection elements in electricalcontact with the plurality of active regions. The connection elementsare configured such that each active region in the plurality can receivean electrical signal independent from other active regions in saidplurality.

These and other further features and advantages of the invention wouldbe apparent to those skilled in the art from the following detaileddescription, taken together with the accompanying drawings, wherein likenumerals designate corresponding parts in the figures, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is front sectional view of a prior art LED chip in contemporaryuse;

FIG. 2 is top plan view of an embodiment of an LED chip incorporatingfeatures of the present invention;

FIG. 3 is top plan view of an embodiment of an LED chip incorporatingfeatures of the present invention;

FIG. 4 is top schematic view of an embodiment of an LED chipincorporating features of the present invention;

FIG. 5 is top schematic view of an embodiment of an LED chipincorporating features of the present invention;

FIG. 6 is a front sectional view of a cross section of the embodiment ofthe LED chip of FIG. 5;

FIG. 7 is a front sectional view of another cross section of theembodiment of the LED chip of FIG. 5;

FIG. 8 is a front sectional view of still another cross section of theembodiment of the LED chip of FIG. 5;

FIG. 9 is a front sectional view of yet another cross section of theembodiment of the LED chip of FIG. 5;

FIG. 10 is a top schematic view of an embodiment of an LED chipincorporating features of the present invention;

FIG. 11 is a top schematic view of an embodiment of an LED chipincorporating features of the present invention;

FIG. 12 is a top plan view of an embodiment of an LED chip incorporatingfeatures of the present invention;

FIG. 13 is a top plan view of an embodiment of an LED chip incorporatingfeatures of the present invention;

FIG. 14 is a top plan view of an embodiment of an LED chip incorporatingfeatures of the present invention;

FIG. 15 is a top plan view of an embodiment of an LED chip incorporatingfeatures of the present invention;

FIG. 16 is a top plan view of an embodiment of an LED chip incorporatingfeatures of the present invention;

FIG. 17 is a top plan view of an embodiment of an LED chip incorporatingfeatures of the present invention;

FIG. 18 is a top plan view of an embodiment of an LED chip incorporatingfeatures of the present invention; and

FIG. 19 is a front sectional view of an embodiment of a lighting deviceincorporating features of the present invention.

DETAILED DESCRIPTION

The present disclosure will now set forth detailed descriptions ofvarious embodiments. These embodiments set forth devices pertaining tolight emitting devices, such as various LED chips and LED devices.Embodiments incorporating features of the present invention allow forthe efficient customization of LED chip beam output through theselective activation of multiple active regions. This allows forimproved customization and greater variable beam output because of theability to independently activate the multiple active regions, all whileutilizing a single LED chip without the necessity of incorporatingcomplicated moving parts, including various reflector and opticcomponents.

Devices incorporating features of the present invention include LEDchips comprising pluralities of separate active regions that areindividually addressable on the same submount. In some embodiments, thediode region of an LED is etched to define two or more active regionsthat are individually contacted. In some embodiments, the multipleactive regions are individually contacted through each comprising theirown cathode contact to the n-type layer of the active region, where themultiple active regions share an anode contact. In some embodiments, themultiple active regions share a cathode contact and are individuallycontacted by their own anode contacts. In some embodiments, the multipleactive regions each comprise their own individual anode and cathodecontacts.

In some embodiments, one or more of the individually addressable activeregions surround one or more other active regions. This allows forefficient control of beam output. By activating only the surroundingouter active region, the beam profile can be wider. By activating onlythe inner surrounded active region, the beam emission profile can bemore narrow. In some embodiments, the multiple active regions areadjacent to one another and are aligned in successive order. This allowsfor precise control over the various regions of the LED chip and isparticularly useful when the chip is installed in a light-emittingdevice, such that different portions of the chip can interact withdifferent portions of the device, for example, in embodiments whereindifferent independently addressable active regions are aligned such thatthey can emit light toward a particular reflective surface or lens,while other active regions are aligned with a different structure toprovide specific beam output profiles. In some embodiments, the multipleactive regions are not aligned or surrounding another active region, forexample, they can be divided into quadrants.

In some embodiments, one or more of the individually addressable activeregions in an LED chip can be driven by a different current than otheractive regions in the chip. This allows for further customization oflight output such as beam shape, intensity and beam emission profile.

Throughout this description, the preferred embodiment and examplesillustrated should be considered as exemplars, rather than aslimitations on the present invention. As used herein, the term“invention,” “device,” “present invention,” or “present device” refersto any one of the embodiments of the invention described herein, and anyequivalents. Furthermore, reference to various feature(s) of the“invention,” “device,” “present invention,” or “present device”throughout this document does not mean that all claimed embodiments ormethods must include the referenced feature(s).

It is also understood that when an element or feature is referred to asbeing “on” or “adjacent” to another element or feature, it can bedirectly on or adjacent the other element or feature or interveningelements or features may also be present. It is also understood thatwhen an element is referred to as being “attached,” “connected” or“coupled” to another element, it can be directly attached, connected orcoupled to the other element or intervening elements may be present. Incontrast, when an element is referred to as being “directly attached,”“directly connected” or “directly coupled” to another element, there areno intervening elements present.

Relative terms, such as “outer,” “above,” “lower,” “below,”“horizontal,” “vertical” and similar terms, may be used herein todescribe a relationship of one feature to another. It is understood thatthese terms are intended to encompass different orientations in additionto the orientation depicted in the figures.

Although the terms first, second, etc. may be used herein to describevarious elements or components, these elements or components should notbe limited by these terms. These terms are only used to distinguish oneelement or component from another element or component. Thus, a firstelement or component discussed below could be termed a second element orcomponent without departing from the teachings of the present invention.As used herein, the term “and/or” includes any and all combinations ofone or more of the associated list items.

The terminology used herein is for describing particular embodimentsonly and is not intended to be limiting of the invention. As usedherein, the singular forms “a,” “an,” and “the” are intended to includethe plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises,”“comprising,” when used herein, specify the presence of stated features,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof.

Embodiments of the invention are described herein with reference todifferent views and illustrations that are schematic illustrations ofidealized embodiments of the invention. As such, variations from theshapes of the illustrations as a result, for example, of manufacturingtechniques and/or tolerances are expected. Embodiments of the inventionshould not be construed as limited to the particular shapes of theregions illustrated herein, but are to include deviations in shapes thatresult, for example, from manufacturing.

It is understood that when a first element is referred to as being“between,” “sandwiched,” or “sandwiched between,” two or more otherelements, the first element can be directly between the two or moreother elements or intervening elements may also be present between thetwo or more other elements. For example, if a first layer is “between”or “sandwiched between” a second and third layer, the first layer can bedirectly between the second and third layers with no interveningelements or the first layer can be adjacent to one or more additionallayers with the first layer and these additional layers all between thesecond and third layers.

It is noted that the terms “layer” and “layers” are used interchangeablythroughout this application. A person of ordinary skill in the art willunderstand that a single “layer” of material may actually compriseseveral individual layers of material. Likewise, several “layers” ofmaterial may be considered functionally as a single layer. In otherwords, the term “layer” does not denote a homogenous layer of material.A single “layer” may contain various material concentrations andcompositions that are localized in sub-layers. These sub-layers may beformed in a single formation step or in multiple steps. Unlessspecifically stated otherwise, it is not intended to limit the scope ofthe invention as embodied in the claims by describing an element ascomprising a “layer” or “layers” of material.

The basic structure of light emitting diodes is generally known in theart and is therefore only briefly discussed herein. The diode region cancomprise two oppositely doped semiconductor layers with an active regiontherebetween. An anode contact ohmically contacts the p-type doped layerand a cathode contact ohmically contacts the doped layer. When a bias isapplied across the doped layers, holes and electrons are injected intothe active region where they recombine to generate light. One suitablesemiconductor material to utilize for the diode region is GaN, althoughany semiconductor material known in the art for use in the manufactureof LEDs are within the scope of this disclosure. Some examplesemiconductor materials include, but not limited to, materialscomprising: Gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs),gallium arsenide phosphide (GaAsP), aluminum gallium indium phosphide(AlGaInP), gallium(III) phosphide (GaP), gallium arsenide phosphide(GaAsP), aluminum gallium phosphide (AlGaP), indium gallium nitride(InGaN), aluminum nitride (AlN), aluminum gallium nitride (AlGaN),aluminum gallium indium nitride (AlGaInN), and combinations thereof.

An LED chip 100 incorporating features of the present invention is shownin FIG. 2. The LED chip 100 is shown in a top plan view, showing thetopmost semiconductor layer of the diode region of the chip, which inthe embodiment shown is an n-type layer, although it is understood thatin some embodiments, the topmost semiconductor layer in the diode regionis a p-type layer. It is further understood that LEDs incorporatingfeatures of the present invention can further comprise variousadditional layers, such as reflector layers or current spreading layersin addition to the semiconductor layers. The LED chip 100 comprises afirst active region 102, a second active region 104, a separation region106, a first cathode contact 108, which contacts the n-type layer of thefirst active region 102, a second cathode contact 110, which contactsthe n-type layer of the second active region 104, and a third cathodecontact 112, which also contacts the n-type layer of the second activeregion 104.

The semiconductor layers are on a common submount 114, forming a singleLED chip device. The submount 114 can be any suitable mounting surfacefor the semiconductor layers, for example, any suitable LED substrateknown in the art. Some example substrates include sapphire, silicon orsilicon carbide substrates. Such a substrate can be a substrate uponwhich the semiconductor layers are grown (a growth substrate) or asubstrate to which the semiconductor layers are later transferred, forexample, as with flip-chip embodiments (a carrier substrate).

A common anode contact, which is not shown due to being positioned onthe bottom surface of the LED chip 100 provides access for electricalcontact to the p-type semiconductor layers of the first and secondactive regions 102, 104. In some embodiments, the submount 114 is aconductive substrate and the anode contact contacts the p-type layerthrough the conductive substrate. It is understood that in embodimentswherein the topmost semiconductor layer is a p-type layer, first, secondand third n-type contacts can instead be replaced by anode contacts andthat a common cathode contact can electrically contact bottommost n-typesemiconductors layer of the LED chip 100.

The first active region 102 and the second active region 104 areseparated by the separation region 106. The purpose of separation region106 is to separate the first and second active regions 102, 104 fromeach other, either through electrical isolation or physical separation,and sufficiently isolate them so electrical signals from the firstcathode contact 108 to the first active region 102 will not provide anelectrical signal to the second active region 104 and so that the secondand third cathode contacts 110, 112 to the second active region 104 willnot provide an electrical signal to the first active region 102.

The separation region 106 can comprise any known configuration or methodsufficient to separate semiconductor layers from one another that isknown in the art. In some embodiments, separation region 106 is formedby etching the semiconductor layers to a degree sufficient to separatethe first active region 102 from the second active region 104. In someembodiments, such as the embodiment shown in FIG. 2, the separationregion 106 is etched to the level of the submount 114 or the underlyinganode contact. In some embodiments, a passivation layer is deposited onthe separation region 106 after etching. Further examples of etchingused to define multiple semiconductor regions can be found in US PatentPublication No. 2013/0264592, assigned to Cree, Inc., which isincorporated herein in its entirety by reference.

One advantage of utilizing etching as the method of forming theseparation region 106 is that etching of a diode region of a chip canprovide a sufficiently narrow separation region 106, such that there aresmaller gaps in die placement than there would be if one were to try toachieve the multiple active region effect by simply placing two separateLED die close together. This allows for creation of more uniformemission and the creation of certain beam patterns not possible inembodiments utilizing multiple LED die.

The first cathode contact 108, the second cathode contact 110 and thethird cathode contact 112 can comprise any form of electrical connectionelements known in the art, for example, bond pads, which can formelectrical connection through the use of wire bonds to outsideelectrical sources and internal and/or integral electrical connectionelements, for example, conductive busses and vias. In the embodimentshown in FIG. 2, the first cathode contact 108 comprises an internal orintegrated connection 116 to the first active region 102, with theinternal connection running integral to the layers of the submount 114and running below, and being electrically isolated from, active region104.

The internal connection 116 is electrically isolated from the secondactive region 104, such that providing electricity to the internalconnection 116 through the first cathode contact 108 will only providean n-type electrical connection to the first active region 102. Thesecond and third cathode contacts 110, 112 comprise bond pads, which canbe connected to an outside electrical source via wire bonds.

One advantage of utilizing an internal or integral connection 116 to thefirst active region 102 is that wire bond connections to the moreinternally-positioned first active region are not necessary. Whilewire-bonding the more outer-positioned second and third cathode contacts110, 112 provides no significant disadvantage, wire-bonding a bond padpositioned in the center of the LED chip 100 where the first activeregion 102 is located can potentially result in the wire bond blockingsome of the emitted light over the top center region. This results ininefficient light extraction and can also cause a disorienting sensationfor viewers.

In some embodiments, internal connection element 116 comprises one ormore internal interconnect elements, which comprise an electricallyconductive element surrounded by passivation material. Such internalinterconnect elements can be formed internal to the submount duringdevice fabrication. Further examples of such internal interconnectionelements can be found in US Patent Publication No. 2014/0070245,assigned to Cree, Inc., which is incorporated herein in its entirety byreference.

One embodiment of a monolithic LED chip comprises a plurality of activeregions on a submount. Integral electrically conductive interconnectelements are included in electrical contact with the active regions andelectrically connecting at least some of the active region in series.One or more integral insulating layers are also included surrounding atleast a portion of the interconnect elements and isolating the portionfrom other elements of the LED chip.

The electrical interconnects can be arranged so that at least a portionis buried or surrounded in electrical insulating material. The submountcan also have a barrier layer that does not extend beyond the edge of orwrap around the portions of the mirror layer, with the portion beingparticularly below the primary emission area of the active regions. Thiscan help minimize the light that might be absorbed during operation,thereby increasing the overall emission efficiency of the activeregions.

In certain embodiments, at least a portion of the interconnects areburied in or surrounded by insulating material to electrically isolatethem from other features in the LED chip. This structure can thenmounted to a separate substrate and bonding layer structure to formmonolithic LED chips with serially interconnected active regions.

Because of the separation region 106 and the configuration of theelectrical connection elements 108, 110, 112, the first active region102 and the second active region 104 are individually addressable. Thisallows for the emission output of the LED chip 100 to be controlledelectrically, rather than through the integration of complex movingparts, such as moving lens and reflector structures. By applying powerto the first active region 102, for example, through the first cathodecontact 108 and the internal connection 116 (thus providing cathodecontact through internal connection 116 and anode contact through thesubmount 114), only the center portion of the LED chip 100 is activatedand emitting light, as the cathode contacts 110, 112 to the secondactive region 104 are not activated. This results in a more narrow beamemission from the LED chip 100. While a single contact 108 and aninternal connection 116 are shown as contacting the first active region102, it is understood that other structures such as bond pads and/orconductive vias can also be utilized. It is further understood thatother electrical connections known in the art can be utilized to provideanode and cathode contacts to the first active region 102.

By applying power to the second active region 104, for example, throughsecond and third cathode contacts 110, 112 (thus providing cathodecontact through the second and third cathode contacts 110, 112 and anodecontact through the submount 114), only the outer portion of the LEDchip 100 is activated and emitting light, as the first cathode contact108 to the first active region 102 is not activated. This results in awider beam emission from the LED chip 100. This effect can be increasedby utilizing the LED chip 100 with further structures, such as variouslenses, optics and reflectors.

One advantage of the individually addressable multiple active regions ofthe LED chip 100, is that these various structures can simply bestationary and do not need to be moveable or otherwise variable toproduce variable emission as the beam output can be varied electricallyas described. While two bond pads 110, 112 are shown as contacting thesecond active region 104, it is understood that one or more internalconnections, conductive vias, a single bond pad and/or more than twobond pads can be utilized to provide electrical contact to the activeregion 104. It is further understood that other electrical connectionsknown in the art can be utilized to provide anode and cathode contactsto the second active regions 104.

In the LED chip 100 of FIG. 2, the first active region 102 is surroundedby the second active region 104. The first active region 102 can bepartially surrounded, or be substantially or completely surrounded (asshown). In some embodiments, such as those discussed in more detailfurther below, the first active region 102 is not surrounded by thesecond active region 104. At least one advantage of having anindividually addressable active region surrounded by anotherindividually addressable active region, is that beam emission can beeven more tightly controlled, for example, easily widening the beamemission by activating the outer active region and narrowing the beamemission by activing the inner active region as discussed above.

While the first active region 102 and the second active region 104 areshown to be roughly square in shape, it is understood that activeregions according to the present disclosure can comprise any number ofshapes as needed to obtain a desired beam output profile. Some shapesinclude any regular or irregular polygon, as well as curved or circularshapes. It is further understood that in embodiments wherein one activeregion surrounds another active region, the shapes of the various activeregions do not need to be identical or even similar. For example, insome embodiments, the inner active region can comprise one shape, suchas a triangle or a square, while the surrounding active region cancomprise another shape, for example, a circular or elliptical shape.Various examples of differently shaped active regions are also set forthfurther below in the present disclosure.

While the embodiment of FIG. 2 above relates to a LED chip having twoactive regions on a common substrate, it is understood that LEDsincorporating features of the present invention can have one or morefurther multiple active regions in the plurality of active regions. FIG.3 shows one example of an LED chip 200, comprising a first active region202, surrounded by a second active region 204, which is in turnsurrounded by a third active region 206.

The first active region 202 and the second active region 204 areseparated by a first separation area 208 and the second active region204 and the third active region 206 are separated by a second separationarea 210. Like with FIG. 2 above, the topmost semiconductor layer is ann-type layer, although it is understood, as previously discussed herein,that in some embodiments, a p-type layer is the topmost layer. Thesemiconductor layers are on a submount 212.

Each of the active regions have electrical connection elements, with afirst cathode contact 214 contacting the first active region 202, asecond cathode contact 216 contacting the second active region 204 and athird cathode contact 218 contacting the third active region 206. Thesecontacts 214, 216, 218 can be provided with power using wire bonds orany configurations that is known in the art. The anode contact is notshown as it is on the bottom surface of the LED chip 200 as in FIG. 2,for example, connected to a conductive substrate. Although theelectrical connection elements 214, 216, 218 are shown in FIG. 2 asbeing bond pads, it is understood that any electrical connectionelements can be utilized, for example, conductive vias though thesubmount and/or one or more layers, busses or internal interconnects asdescribed above.

The various embodiments of LED chips disclosed herein can comprisemultiple active regions of various and differing shapes to produce adesired beam profile. In the LED chip 200 of FIG. 3, the first andsecond active regions 202, 204 are circular in shape, whereas the thirdactive region 206 is roughly square with a circular inner surface. Thisshape layout, coupled with the multiple surrounding active regionconfiguration, can potentially provide even greater control over beamemission. By only activating the third active region 206, the peripheryof the LED chip 200 is emissive, providing a relatively wide beamoutput. In contrast, activating the second active region 204 or thefirst active region 202 will provide a more narrow beam output, with thebeam output of the centermost active region (first active region 202)providing the most narrow beam output.

While the above-described embodiments of FIGS. 2-3 comprise aconfiguration wherein an active region is surrounded by another activeregion, other configurations are also possible. In some embodiments,multiple active regions are configured adjacent to each other one afteranother in successive order. One such configuration is shown in FIG. 4,which shows LED chip 300 comprising four separate active regions 302,304, 306, 308 on a common submount 309, separated by separation regions310, 312, 314. The linear configuration of the active regions 302, 304,306, 308 of the LED chip 300 allows for another different type of beamoutput control. In some embodiments, the LED chip 300 is used inconjunction with an optic or reflector, for example, in automobileheadlight embodiments or flashlight embodiments. In these embodiments,different active regions can line up with different portions of an opticor reflector can be individually activated to produce light that willinteract with a particular feature of an optic or reflector to provide adesired beam output.

In addition to the different active region configuration, the LED chip300 of FIG. 4 differs from the LED chip 200 of FIG. 3 and the LED chip100 of FIG. 2 in that the active regions 302, 304, 306, 308 of LED chip300 of FIG. 4 do not share a common anode contact, but instead eachindividual active region has its own individual anode contacts 316, 318,320, 322, as well as its own individual cathode contacts 324, 326, 328,330. In this embodiment, the anode and cathode contacts comprise bondpads in lateral geometry, both being accessible from the top surface ofthe LED chip 300. This can be achieved, for example, by etching away aportion of the top n-layer such that topside contact to then underlyingp-layer can occur or through various methods of forming lateral geometrydevices that are known in the art. In some embodiments, the contacts arein vertical geometry such that one of the contacts is accessible fromthe top surface of the LED chip 300 and the other is accessible from thebottom surface.

Another linear adjacent multiple active region LED chip 400 is shown inFIG. 5 which, like in FIG. 4, shows four active regions 402, 404, 406,408, separated by separation regions 410, 412, 414. Unlike in FIG. 4,the active regions 402, 404, 406, 408 of the LED chip 400 of FIG. 5share a common cathode contact 416 and each active region comprisesindividual anode contacts with a first anode contact 418 contacting thefirst active region 402 with a first anode internal connection 420, asecond anode contact 422 contacting the second active region 404 with asecond anode internal connection 424, a third anode contact 426contacting the third active region 406 with a third anode internalconnection 428 and a fourth anode contact 430 contacting the fourthactive region 408 with a fourth anode internal connection 432. Thecommon cathode contact 416 can be an elongated bond pad as shown,allowing the individual active regions 402, 404, 406, 408 to connect tothe cathode contact 416 at different points along its length or anyconnection structure known in the art. The individual anode contacts418, 422, 426, 430 can be individualized bond pads allowing each of theactive regions 402, 404, 406, 408 to be individually addressable throughtheir anode connection or any connection structure known in the art.

Four cross section lines A, B, C and D are shown in FIG. 5 correspondingto different depths within the LED chip 400. These cross sectionscorrespond to front sectional views shown in FIGS. 6-9, which illustrateexample internal connection configurations that can be utilized with theLED chip 400. FIG. 6 shows a front sectional view 500 corresponding tocross section line A in FIG. 5. The sectional view 500 shows the first,second, third and fourth active regions 402, 404, 406, 408 and the firstsecond and third separation regions 410, 412, 414. FIG. 6 also shows thecommon cathode contact 416 contacting the n-type layer 502 of the firstactive region 402 through a first cathode internal connection 504 andthe first anode contact 418 contacting the p-type layer 506 of the firstactive region through the first anode internal connection 420.

The submount 510 comprises a substrate 512, which can be made of anysuitable substrate material that is known in the art, such as thematerials discussed herein. The submount 510 can further comprise anisolation layer 514, which can comprise many different materials, withthe preferred material being an electrically insulating material, suchas a dielectric. In some embodiments, the isolation layer 514 comprisesoxides, nitrides or oxynitrides of elements Si and Al. In someembodiments, all or a portion of the top surface of the LED chip 400 canbe coated with a passivation layer, which can provide additionalprotection to the LED chip 400 and/or electrical isolation between theindividual active regions 402, 404, 406, 408.

The first cathode internal connection 504 can comprise a firstconductive interconnect 516 and an n-type via 518, which is isolatedfrom the p-type layer 506 by a passivation layer 519, which can compriseany suitable insulating material, for example, materials similar to theisolation layer 514. The first anode internal connection 420 cancomprise a second conductive interconnect 520. The first cathodeinternal connection 504 and the first anode internal connection 420 canalso comprise any internal interconnect configurations that are known inthe art. The first cathode internal connection 504 and the first anodeinternal connection 420 can comprise any electrically conductivematerial, for example, various metals and/or materials known to be usedwith interconnect elements known in the art. In some embodiments, theseinternal connections are formed internally to the submount 510 duringdevice fabrication.

While the LED chip 400 shown in the sectional view 500 of FIG. 6comprises an n-type layer 502 as the topmost semiconductor layer and anp-type layer 506 as the bottommost semiconductor layer, it is understoodby one of ordinary skill in the art that the same principles describedherein can be utilized to provide electrical connection to individualactive regions in LED chips embodiments wherein the p-type layer is thetopmost layer and the n-type layer is the bottommost layer. Furthermore,it is understood that while a basic submount 510 and active region 402,404, 406, 408 configuration is shown herein, more complex LED chipstructures can incorporate features of the present invention. Forexample, various barrier layer, mirror layer and reflective layerconfigurations can be utilized with the LED chip. Further examples ofvarious internal interconnect configurations and LED chips and packagesutilizing them can be found in US Patent Publication 2014/0070245, whichis assigned to Cree, Inc., and which is incorporated herein in itsentirety by reference.

The other cross sections B, C, D of FIG. 5 are shown in FIGS. 7-9. FIG.7 shows a front sectional view 600 corresponding to cross section line Bin FIG. 5. The sectional view 600 shows the first, second, third andfourth active regions 402, 404, 406, 408 and the first second and thirdseparation regions 410, 412, 414. FIG. 7 also shows the common cathodecontact 416 contacting the n-type layer 602 of the second active region404 through a second cathode internal connection 604 and the secondanode contact 424 contacting the p-type layer 606 of the second activeregion through the second anode internal connection 424. While thesecond active region 404 is connected to the same cathode contact 416 asis the first active region 402, as is shown in FIG. 6, FIG. 7 shows thatthe second active region 404 is connected to a different anode contact422 that the first active region 402. Accordingly, an electrical signalapplied to the common cathode 416 and the second anode contact 422 willindividually address the second active region 404, without addressingthe first active region 402.

FIG. 8 shows a front sectional view 700 corresponding to cross sectionline C in FIG. 5. The sectional view 700 shows the first, second, thirdand fourth active regions 402, 404, 406, 408 and the first second andthird separation regions 410, 412, 414. FIG. 8 also shows the commoncathode contact 416 contacting the n-type layer 702 of the third activeregion 406 through a third cathode internal connection 704 and the thirdanode contact 426 contacting the p-type layer 706 of the third activeregion through the third anode internal connection 428. This view 700shows how the third active region 406 is individually addressable fromthe first and second active regions 402, 404.

FIG. 9 shows a front sectional view 800 corresponding to cross sectionline D in FIG. 5. The sectional view 800 shows the first, second, thirdand fourth active regions 402, 404, 406, 408 and the first second andthird separation regions 410, 412, 414. FIG. 9 also shows the commoncathode contact 416 contacting the n-type layer 802 of the fourth activeregion 408 through a fourth cathode internal connection 804 and thefourth anode contact 430 contacting the p-type layer 806 of the fourthactive region through the fourth anode internal connection 432. FIGS.6-9, when taken together, further clarify the relationship between thecommon cathode contact 416, the individual anode contacts 418, 422, 426,430 and the individual active regions 402, 404, 406, 408, and show howselective application of an electrical signal results in the individualactive regions being separately addressable.

Another variant electrical connection element configuration is shown inFIG. 10 which, like in FIG. 5, shows an LED chip 900 comprising fouractive regions 902, 904, 906, 908, separated by separation regions 910,912, 914. Unlike in FIG. 5, the active regions 902, 904, 906, 908 of theLED chip 900 of FIG. 10 share a common anode contact 916 and each activeregion comprises individual cathode contacts with a first cathodecontact 918 contacting the first active region 902 with a first internalconnection 920, a second cathode contact 922 contacting the secondactive region 904 with a second internal connection 924, a third cathodecontact 926 contacting the third active region 906 with a third internalconnection 928 and a fourth cathode contact 930 contacting the fourthactive region 908 with a fourth internal connection 932. The commonanode contact 916 can include any connection structure known in the artor can be an elongated bond pad like the cathode in FIG. 5, while theindividual cathode contacts 918, 922, 926, 930 can be separate bond padsallowing for individualized connection.

Still another variant electrical connection element configuration isshown in FIG. 11, which like in FIGS. 4-10 above shows an LED chip 1000comprising four adjacent active regions 1002, 1004, 1006, 1008 arrangedin linear successive fashion, separated by separation regions 1010,1012, 1014. Like in FIG. 4, each individual active region 1002, 1004,1006, 1008 is connected to its own separate individual anode and cathodecontact. Unlike in FIG. 4, wherein bond pads alone are utilized, theelectrical connection elements in the LED chip 1000 of FIG. 11 utilizesinternal connection elements.

Utilizing internal connections, such as those described above, FIG. 11shows the first active region 1002 being contacted by a first cathodecontact 1016 and a first anode contact 1018, the second active region1004 being contacted by a second cathode contact 1020 and a second anodecontact 1022, the third active region 1006 being contacted by a thirdcathode contact 1024 and a third anode contact 1026, and the fourthactive region 1008 being contacted by a fourth cathode contact 1028 anda fourth anode contact 1030. This configuration can be advantageous asit allows for individual connection of one or more active regions to itsown anode and cathode contact without utilizing wire bonds to bond pads,which can block some of the emitted light.

Additional example active region shapes are shown in FIGS. 12-15, whichshow configurations similar to those set forth in FIG. 2 above,utilizing a first active region surrounded by a second active region.FIG. 12 shows an LED chip 1100, comprising a first active region 1102and a second active region 1104 separated by a separation region 1106.First and second cathode bond pads 1108, 1110 are configured to provideelectrical contact to the second active region 1104 and a third cathodecontact 1112, utilizes an internal connection 1114 to make electricalcontact to the surrounded first active region 1102. As with FIG. 2above, the anode contact is common to both active regions 1102, 1104 andis not shown. Unlike in FIG. 2, the first active region 1102 isrectangular rather than square. This provides a wider lateral beamemission pattern when the first active region 1102 is activated thanthat of the square first active region 102 of FIG. 2 discussed above.

Another example variant active region shape is set forth in FIG. 13,which shows an LED chip 1200, comprising a first active region 1202 anda second active region 1204 separated by a separation region 1206. Firstand second cathode bond pads 1208, 1210 are configured to provideelectrical contact to the second active region 1204 and a third cathodecontact 1212, utilizes an internal connection 1214 to make electricalcontact to the surrounded first active region 1202. As with FIG. 2above, the anode contact is common to both active regions 1202, 1204 andis not shown. Unlike in FIG. 2, the first active region 1202 istriangular rather than square. This provides a narrower beam emissionpattern from the upper two corners 1216, 1218 of the LED chip 1200 whenthe first active region 1202 is activated than that of the square firstactive region 102 of FIG. 2 discussed above.

Still another example variant active region shape is set forth in FIG.14, which shows an LED chip 1300, comprising a first active region 1302and a second active region 1304 separated by a separation region 1306.First and second cathode bond pads 1308, 1310 are configured to provideelectrical contact to the second active region 1304 and a third cathodecontact 1312, utilizes an internal connection 1314 to make electricalcontact to the surrounded first active region 1302. As with FIG. 2above, the anode contact is common to both active regions 1302, 1304 andis not shown. Unlike in FIG. 2, the first active region 1302 ishexagonal rather than square. The provides a wider beam emission patternfrom the LED chip 1300 when the first active region 1302 is activatedthan that of the square first active region 102 of FIG. 2 discussedabove.

Yet another example variant active region shape is set forth in FIG. 15,which shows an LED chip 1400, comprising a first active region 1402 anda second active region 1404 separated by a separation region 1406. Firstand second cathode bond pads 1408, 1410 are configured to provideelectrical contact to the second active region 1404 and a third cathodecontact 1412, utilizes an internal connection 1414 to make electricalcontact to the surrounded first active region 1402. As with FIG. 2above, the anode contact is common to both active regions 1402, 1404 andis not shown. Unlike in FIG. 2, the first active region 1402 isstar-shaped rather than square. This provides a narrower beam emissionpattern from the four corners 1416, 1418, 1420, 1422 of the LED chip1400 when the first active region 1402 is activated than that of thesquare first active region 102 of FIG. 2 discussed above.

Further configurations for multiple active regions on a LED chip are setforth in FIGS. 16 and 17, which show a plurality of active regions thatare neither arranged in successive order, nor comprising an activeregion substantially surrounded by another active region. FIG. 16 showsan LED chip 1500 comprising four active regions 1502, 1504, 1506, 1508,divided into quadrants by a separation region 1510. Each active region1502, 1504, 1506, 1508 comprises its own individual cathode contact1514, 1516, 1518, 1520, with the anode contact being bonded to theunderside of the LED chip 1500 and common to all active regions 1502,1504, 1506, 1508 and not being shown. This configuration allows forindividual control of beam emission of each of the four quadrants of theLED chip 1500.

Another alternate active region configuration is shown in FIG. 17, whichshows an LED chip 1600, which is similar to LED chip 1500 in FIG. 16above in that it comprises four active regions 1602, 1604, 1606, 1608,divided by a separation region 1610. Each active region 1602, 1604,1606, 1608 comprises its own individual cathode contact 1614, 1616,1618, 1620, with the anode contact being bonded to the underside of theLED chip 1600 and common to all active regions 1602, 1604, 1606, 1608and not being shown. Unlike LED chip 1500 in FIG. 16 above, the fourquadrants of LED chip 1600 are divided such that activation of both thefirst active region 1602 and the fourth active region 1608 can provide awider lateral beam output and activation of both the second activeregion 1604 and the third active region 1606 can provide a widervertical beam output.

Another example of multiple surrounding active regions, similar to thatset forth in FIG. 3 above is set forth in FIG. 18, which shows an LEDchip 1700 comprising a first active region 1702 surrounded by a secondactive region 1704 and separated from the second active region by afirst separation region 1706. The second active region 1704 issurrounded by a third active region 1708 and separated from the secondactive region by a first separation region 1710. Each active region1702, 1704, 1708 comprises its own individual cathode contact 1712,1714, 1716, with the anode contact being bonded to the underside of theLED chip 1700 and common to all active regions 1702, 1704, 1708 and notbeing shown.

The LED chip 1700 in FIG. 18 differs from the LED chip 200 in FIG. 3both in the shape of the active regions and in the fact that the firstand second active regions 1702, 1704 in the LED chip 1700 of FIG. 18comprise a shape that is different from one another—the first activeregion 1702 is square, whereas the second active region 1704 isrectangular. This allows the LED chip 1700 to have three different beammodes with further varying features. For example, activation of thefirst active region 1702 would provide a narrow beam output. Activationof the third active region 1708 would provide a wide beam output.Activation of the second rectangular-shaped active region 1704 wouldprovide a beam output in between that of the first and third activeregions 1702, 1708, but would also provide a wider lateral beam outputdue to its rectangular shape.

While being able to control and adjust beam output utilizing onlyselective electrical activation of desired active regions in an LED chipis advantageous alone, some particularly useful application for thistechnology include automatic lighting, such as in car headlights, wheredifferent beam modes are desired and flashlights where a simpler, fixed(non-movable) optic can be utilized and still achieve a variable beampattern.

An example lighting device 1800 incorporating embodiments according tothe present disclosure is shown in FIG. 19. The lighting device 1800comprises a multiple active region LED 1802, for example, such as thosedisclosed in the embodiments of the present disclosure, which isconfigured with a reflector 1804 and/or an optic 1806. The reflector canbe any reflector that is known in the art, for example a diffuse orspecular reflector. In the embodiment shown, the reflector 1804comprises a reflector-cup configuration with the LED 1802 configuredinside the reflector 1804. The optic 1806 can be any optic known in theart, for example, a lens such as a diffusive lens. In some embodiments,the optic 1806 comprises a Total Internal Reflection (TIR) spot optic.An advantage of the lighting device 1800 is that since the multipleactive regions in the LED 1802 are individually addressable, thereflector 1804 and the optic 1802 can be fixed (i.e. non-movable) andthese structure's interactions with the variable beam output can furtherfacilitate the creation of different specific beam patterns.

It is understood that while many of the embodiments specifically setforth herein are shown such that each active region in the plurality isindividually addressable, it is possible to have configurations wheremultiple active regions are only addressable together in series. Forexample, an LED chip comprising four active regions can be configured,such that two of the regions are only addressable together while theother two are each individually addressable.

Although the present invention has been described in detail withreference to certain preferred configurations thereof, other versionsare possible. Embodiments of the present invention can comprise anycombination of compatible features shown in the various figures, andthese embodiments should not be limited to those expressly illustratedand discussed. Therefore, the spirit and scope of the invention shouldnot be limited to the versions described above.

The foregoing is intended to cover all modifications and alternativeconstructions falling within the spirit and scope of the invention asexpressed in the appended claims, wherein no portion of the disclosureis intended, expressly or implicitly, to be dedicated to the publicdomain if not set forth in the claims.

We claim:
 1. A light emitting diode (LED) chip, comprising: a submountcomprising an insulating material, the submount comprising a firstsurface, a second surface opposing the first surface, a first end, and asecond end; a plurality of active regions on or above the first surfaceof said submount and intermediately arranged between the first end andthe second end; metal connection elements in electrical contact withsaid plurality of active regions, wherein said metal connection elementsare configured such that at least one active region of said plurality ofactive regions can receive an electrical signal independent from otheractive regions of said plurality of active regions, and at least one ofsaid metal connection elements comprises an internal interconnectelement including (i) a laterally-extending metal element buried withinthe insulating material of said submount in a direction substantiallyparallel to the plurality of active regions and surrounded from aboveand below by the insulating material, and (ii) first and secondvertically-extending metal elements that contact the laterally-extendingmetal element and that are laterally spaced relative to one another,wherein a portion of the insulating material is arranged between thelaterally-extending metal element and the plurality of active regions,and wherein at least portions of the first and secondvertically-extending metal elements are laterally bounded by theinsulating material; one or more anode contacts arranged on the firstsurface proximate to the first end; and one or more cathode contactsarranged on the first surface proximate to the second end; wherein eachactive region of the plurality of active regions is arranged insuccessive order from the one or more anode contacts and the one or morecathode contacts; wherein at least one of the following items (a) or (b)comprises multiple contacts: (a) the one or more anode contacts, and (b)the one or more cathode contacts; wherein the LED chip is devoid of anyanode contacts and any cathode contacts arranged on the first surfacebetween different active regions of the plurality of active regions; andwherein each active region of the plurality of active regions is coupledwith a different pair of (i) the one or more anode contacts and (ii) theone or more cathode contacts, by the metal connection elements.
 2. TheLED chip of claim 1, wherein at least one active region of saidplurality of active regions comprises a different shape from anotheractive region of the plurality of active regions.
 3. The LED chip ofclaim 1, wherein at least one of said metal connection elementscomprises a bond pad in electrical contact with one active region ofsaid plurality of active regions.
 4. The LED chip of claim 1, whereinsaid metal connection elements comprise a plurality of cathodeconnection elements and a plurality of anode connection elements, andeach active region of said plurality of active regions electricallycontacts a different cathode connection element of the plurality ofcathode connection elements and a different anode connection element ofthe plurality of anode connection elements.
 5. The LED chip of claim 4,wherein each cathode connection element of the plurality of cathodeconnection elements comprises an integral interconnect element and eachanode connection element of the plurality of anode connection elementscomprises an integral interconnect element.
 6. The LED chip of claim 1,wherein said one or more cathode contacts comprises a plurality ofcathode bond pads in electrical contact with said plurality of activeregions, and said one or more anode contacts comprises a plurality ofanode bond pads in electrical contact with said plurality of activeregions.
 7. The LED chip of claim 1, wherein each active region of saidplurality of active regions electrically contacts a separate cathodeconnection element and electrically contacts a common anode connectionelement.
 8. The LED chip of claim 1, wherein each active region of saidplurality of active regions electrically contacts a common cathodeconnection element and electrically contacts a separate anode connectionelement.
 9. The LED chip of claim 1, wherein the insulating materialcomprises a unitary insulating material.
 10. The LED chip of claim 1,further comprising at least one plurality of series-connected activeregions that is addressable separately from active regions of theplurality of active regions.
 11. A light emitting device comprising: alight emitting diode (LED) chip comprising: a submount comprising aninsulating material, the submount comprising a first surface, a secondsurface opposing the first surface, a first end, and a second end; aplurality of active regions on or above the first surface of saidsubmount and intermediately arranged between the first end and thesecond end; metal connection elements in electrical contact with saidplurality of active regions, said metal connection elements beingconfigured such that each active region of said plurality of activeregions can receive an electrical signal independent from other activeregions of said plurality of active regions; a reflector cup containingsaid plurality of active regions; one or more anode contacts arranged onthe first surface proximate to the first end; and one or more cathodecontacts arranged on the first surface proximate to the second end;wherein at least one metal connection element of said metal connectionelements comprises an internal interconnect element including (i) alaterally-extending metal element buried within the insulating materialof said submount in a direction substantially parallel to the pluralityof active regions and surrounded from above and below by the insulatingmaterial, and (ii) first and second vertically-extending metal elementsthat contact the laterally-extending metal element and that arelaterally spaced relative to one another, wherein a portion of theinsulating material is arranged between the laterally-extending metalelement and the plurality of active regions, and wherein at leastportions of the first and second vertically-extending metal elements arelaterally bounded by the insulating material; wherein each active regionof the plurality of active regions is arranged in successive order fromthe one or more anode contacts and the one or more cathode contacts;wherein at least one of the following items (a) or (b) comprisesmultiple contacts: (a) the one or more anode contacts, and (b) the oneor more cathode contacts; wherein the LED chip is devoid of any anodecontacts and any cathode contacts arranged on the first surface betweendifferent active regions of the plurality of active regions; and whereineach active region of the plurality of active regions is coupled with adifferent pair of (i) the one or more anode contacts and (ii) the one ormore cathode contacts, by the metal connection elements.
 12. The lightemitting device of claim 11, wherein each active region of saidplurality of active regions electrically contacts a different cathodeconnection element and a different anode connection element.
 13. Thelight emitting device of claim 11, further comprising an optic over saidLED chip.
 14. The light emitting device of claim 13, wherein said opticcomprises a lens.
 15. The light emitting device of claim 11, wherein thelight emitting device is configured to adjust a pattern of an outputbeam by individually controlling each active region of the plurality ofactive regions.
 16. The light emitting device of claim 11, wherein theinsulating material comprises a unitary insulating material.
 17. Thelight emitting device of claim 11, wherein the LED chip comprises atleast one plurality of series-connected active regions that isaddressable separately from active regions of the plurality of activeregions.